Dyeing process



Patented July 18, 1961 2,992,877 DYEING PROCESS Walter Hees,Koln-Hohenberg, and Otto Schneider, Koln- Flittard, Germany, assignorsto Farhenfabrilren Bayer Aktiengesellschaft, Leverkusen, Germany, acorporation of Germany No Drawing. Filed Aug. 13, 1957, Ser. No. 677,845Claims priority, application Germany Aug. 30, 1956 4 Claims. (Cl. 855)The present invention relates to the dyeing of articles from polyestersor cellulose triacetate with disperse dyestuffs; more particularly itconcerns a process for the dyeing of these articles with dispersedyestuffs which consists in carrying out the dyeing in the presence ofan ester of alkyl groups-containing salicylic acids.

As esters of alkyl groups-containing salicylic acids are particularlysuitable the esters of low molecular weight aliphatic alcohols withsalicylic acids substituted by low molecular weight alkyl groups, suchas the methyl esters of: ortho-, metaor para-cresotic acid.

These esters which are water-insoluble, are preferably used in thedyebath in the form of an emulsion, prepared with anion-active ornon-ionic emulsifiers.

The requisite amounts of the esters may easily be as certained in eachcase by preliminary tests; in general, amounts of 2-6 grams per litre ofdyebath, in accordance with the desired depth of the dyeing, will besufficient.

As disperse dyestufis there may be used the dyestuffs known under thisdesignation; cf. for example Diserens, Die neuesten Fortschritte in derAnwendung der Farbstofie, Basel 1949, volume 2, p. 254 seq.

The process according to the invention allows of dyeing articles, i.e.threads, fibres, fabrics and foils, from polyesters of the polyethyleneterephthalate type as well as from cellulose triacetate in deeper shadeswith disperse dyestufis than can be attained in the presence of theesters of salicylic acids already proposed and which are unsubstitutedor substituted by chlorine, nitro-, hydroxyor amino-groups.

The following examples serve to illustrate the invention without,however, limiting the scope thereof.

Example 1 Polyester fibres from polyethylene terephthalate areintroduced into a bath having a liquor-to-goods ratio of 40:1 whichcontains per litre 0.75 gram of the disperse dyestufl?1-amino-4-hydroxy-2-bromoanthraquinone and grams of a mixture of 83parts by weight of the methyl-ester of o-cresotic acid and 17 parts byweight of an emulsifier mixture of equal parts of an aralkyl sulphonateand a non-ionic polyglycol ether. The goods are then dyed in usualmanner at -98 C. for 2 hours. A deep red dyeing is thus obtained havingexcellent fastness to light.

Example 2 Polyester fibres from polyethylene terephthalate areintroduced into a bath having a liquor-to-goods ratio of 40:1 whichcontains per litre 0.75 gram of the disperse dyestufil-hydroxy-4-(p-tolyl)amino-anthraquinone and 5 grams of a mixture of 83parts by weight of a mixture of methyl esters of ortho-, metaorpara-cresotic acid and 17 parts by weight of the emulsifier mixtureindicated in Example 1. The dyeing effected in usual manner at 96-98 C.for 2 hours yields a deep blue shade exhibiting excellent fastness tolight.

We claim:

1. A process for the dyeing of articles from a member of the groupconsisting of polyesters and cellulose triacetate with dispersedyestuffs which comprises carrying out the dyeing in the presence of anester of a low molecular weight aliphatic alcohol with a salicylic acidsubstituted in the benzene ring by a low molecular weight alkyl group.

2. A process according to claim 1 wherein the dyeing is carried out inthe presence of the methyl ester of a cresotic acid.

3. A process according to claim 1 wherein the dyeing is carried out inthe presence of a mixture of methyl esters of ortho-, meta-, andpara-cresotic acid.

4. A process according to claim 1 wherein the dyeing is carried out inthe presence of the methyl ester of orthocresotic acid.

References Cited in the file of this patent UNITED STATES PATENTS2,881,045 Mecco Apr. 7, 1959 FOREIGN PATENTS 579,896 France Oct. 25,1924 OTHER REFERENCES Du Pont: The Technical Bulletin, vol. 8, No. 2,pp. 69-78, June 1952.

Zimmerman: Amer. Dyestufi Rep., pp. 296-302, April 25, 1955.

Fern: Journ. Soc. Dyers and Colourists, vol. 71, pp. 840-856, December1955.

1. A PROCESS FOR THE DYEING OF ARTICLES FROM A MEMBER OF THE GROUPCONSISTING OF POLYESTERS AND CELLULOSE TRIACETATE WITH DISPERSEDYESTUFFS WHICH COMPRISES CARRYING OUT THE DYEING IN THE PRESENCE OF ANESTER OF A LOW MOLECULAR WEIGHT ALIPHATIC ALCOHOL WITH A SALICYLIC ACIDSUBSTITUTED IN THE BENZENE RING BY A LOW MOLECULAR WEIGHT ALKYL GROUP.